<html>
<head>
<script type="text/javascript">
function removeOption()
  {
        var x=document.getElementById("mySelect")
        x.remove(x.selectedIndex)
  }
</script>
</head>
<body>

<form>
<select id="mySelect">
  <option>Apple</option>
  <option>Pear</option>
  <option>Banana</option>
  <option>Orange</option>
</select>
<input type="button" onclick="removeOption()"
value="Remove option">
</form>

<button id="deleteDivBtn">删除div</button>

<div id="deleteDiv">
      我是div
</div>

<script>
    deleteDivBtn.onclick=function(){
        deleteDiv.remove()
    }
</script>

</body>
</html>